Create 1254_Number of Closed Islands.cpp

Graph/1254_Number of Closed Islands.cpp

@@ -0,0 +1,50 @@
+class Solution {
+public:
+    int closedIsland(vector<vector<int>>& grid) {
+        int m = grid.size();
+        int n = grid[0].size();
+        vector<vector<bool>> visit(m, vector<bool>(n));
+        int count = 0;
+        for(int i = 0; i < m; i++){
+            for(int j = 0; j < n; j++){
+                if(grid[i][j] == 0 && !visit[i][j] && bfs(i, j, m, n, grid, visit)){
+                    count++;
+                }
+            }
+        }
+        return count;
+    }
+
+
+
+    bool bfs(int x, int y, int m, int n, vector<vector<int>>& grid, vector<vector<bool>>& visit){
+        queue<pair<int,int>> q;
+        q.push({x, y});
+        visit[x][y] = 2;
+        bool isclosed = true;
+
+        vector<int> dirx{0, 1, 0, -1};
+        vector<int> diry{-1, 0, 1, 0};
+
+        while(!q.empty()){
+            x = q.front().first;
+            y = q.front().second;
+            q.pop();
+
+            for(int i = 0; i < 4; i++){
+                int r = x + dirx[i];
+                int c = y + diry[i];
+                if(r < 0 || r >= m || c < 0 || c >= n){
+                    isclosed = false;
+                }
+                else if(grid[r][c] == 0 && !visit[r][c]){
+                    q.push({r, c});
+                    visit[r][c] = true;
+                }
+            }
+        }
+
+        return isclosed;
+    }
+
+};